I got the message far after the Lifetime expiration, though another user was logged in, what might be the cause?

The source of the issue is that the Lifetime performs not as expected when sending to Computers, as the DA agent snatches incoming message for all users, even though some of them are currently offline.

The message is being sent by broadcast.

The DA agent on the computer with multiple users sends the request to server (signature contains not only the user’s name, but also the name of computer).

Because the message was sent as Broadcast, the Computer is in the list of recipients.

DA agent receives two messages: one for current user, other for the Computer (for all users).

User gets the message which was intended for him.

After client restart, second user gets the message too, because DA agent’s local database already contains the message for all users.